Yes, i know, it's good if you know math, since i'm only 13 so don't ask me about maths mate
Good if it's a hobby! Then! Next you should learn about LOGIC , since i heard that coding savenload uses LOGIC O_O, good luck + rep if i can
Actually, since Encoder came out, you haven't really needed to code save/load from scratch for good quality.
And I really don't recommend an ORPG as a starter project... even the most simple ORPG maps consist of at least 10 pretty hardcore systems.
Here is a save/load tutorial to show you how much works goes into each system-
http://www.hiveworkshop.com/forums/jass-ai-scripts-tutorials-280/saving-loading-192851/
And this is just systems... you also have to do balancing (almost more work than the systems themselves), content, terraining... >.>
If you want a higher quality ORPG, then you are talking many, many systems. For a high quality
hero line wars map, I think I had around 25 systems, and that was a hero line wars map, which doesn't even compare to an orpg.
Each system can have anywhere from 600 lines to 2000 lines of code, requires lots of debugging, and they each have to be implemented into the map.
From there, you have to plan the map code (design so that it is all organized and easily read). If the code isn't planned, then it'll be a chaotic jumble.
Also, for ORPGs nowadays, you there are 2 styles of combat. Full custom combat or wc3 combat, and for wc3 combat you'd want to be using this-
http://www.hiveworkshop.com/forums/jass-functions-413/extension-advanced-damage-event-187241/
There is another more advanced library planned, but it's still being developed.
And then there are tons of data structures you have to learn, like linked lists, various trees.. etc etc..
I really don't suggest making an ORPG your first project. Try a maze, footmen wars, tower wars, or tower defense map instead. Work your way up to an ORPG.
Also, you don't have to be a master coder to make an ORPG, but if you aren't, your ORPG won't be able to compete with the other projects out there like TKoK or Dark Invasion 2.
As far as math is concerned, when I work on stuff now, I am using calc 2/3 in order to come up with the algorithms to do what I need to do. Trig is useful for the very, very basics, but you really want calc 2 minimum in order to do anything cool. College level modern geometry is also very useful.
Try to master advanced stuff with parametric equations (many variables, etc), and familiarize yourself with different coordinate systems (polar/cartesian coordinate systems are the bare basics). There is the cylindrical, hyperbolic, spherical, etc coordinate systems. There are many =P, and they will be very useful when you want to get into the cooler stuff.
